WFU Physics Colloquium

TITLE: First-Principles Investigation of Electronic Properties in Sodium-ion Electrolytes for Solid-state Battery Materials

SPEAKER: Larry E. Rush Jr.

TIME: Friday April 21, 2017 at 12:30 PM

PLACE: Room 009 Scales Fine Arts Center

Storing energy and converting it to something useful has been a difficult problem for humanity, especially when one adds additional constraints such as solving this issue in a safe and cost-effective manner (i.e. just think about Samsung’s explosive battery issue). Batteries are an important component for solving our societal energy demands because they are able to convert electrochemical energy to electrical energy in a way that allows us to take advantage of its portability and effectiveness for off-grid usage. Lithium-ion solid-state batteries are widely used in numerous industries including automotive (i.e. Tesla’s electric vehicles and the LAPD’s stealthy electric motorcycles), portable electronics, medical devices, and so forth, but lithium has the drawback of being expensive, it has the need to be protected from over-charging during the charge/discharge cycle, and lithium-ion batteries have to be transported in a restricted manner due to the lack of air-stability within the material; therefore, the demand for seeking an alternative to lithium-ion batteries has increased.

Sodium-ion solid-state batteries are ideal candidates for replacements to its lithium counterparts because sodium lies in the same group on the periodic table as lithium—thus it has similar chemical properties to lithium—and sodium is much more abundant than lithium, which makes it a cost-effective and geopolitically-neutral alternative. Another important feature for sodium-ion battery materials is the fact that the sodium ions seem to have higher intercalation than lithium ions in solid-state electrolytes, meaning that sodium ions are able to reversibly seep through layers within the electrolyte better than lithium ions during the charge/discharge cycle based on research presented at various institutions. This work, however, will look to further explore the boundaries for sodium-ion containing electrolytes as battery materials by investigating the interface properties of Na₃SbS₄ with metallic sodium, in order to simulate the electronic effects that occur when the anode comes in contact with the electrolyte during cycling of the battery. Furthermore, this work will illuminate a structural puzzle between Na₄P₂S₆ and Li₄P₂S₆, to expand on the electronic differences between sodium-ion solid-state electrolytes and lithium-ion solid-state electrolytes in battery materials.